1. Field of the Invention
The present invention relates to a back-up alarm device of construction equipment or a vehicle including an optical human sensing part and a human sensing part. More particularly, the present invention relates to a human sensing back-up alarm device capable of detecting the rear of construction equipment or a vehicle by using an optical human sensing part when the construction equipment or the vehicle backs up, generating a loud sound for a predetermined period of time by using a speaker if a human or a vehicle is detected behind the construction equipment or the vehicle to ensure safety of the humans and vehicles, and minimizing ambient noise by generating a low sound when there are no humans or vehicles behind the construction equipment or the vehicle.
2. Description of the Prior Art
Conventionally, when construction equipment, such as a loader, a forklift truck, an excavator or a bulldozer, or a vehicle, such as a dump truck or a cargo truck, backs up, a back-up alarm device operates together with a back-up lamp by means of a switch attached to a reverse gear.
The above back-up lamp and the back-up alarm device are installed in the construction equipment in order to prevent accidents caused by the construction equipment being operated in a large working field where many workers are on the job.
However, various back-up alarm devices capable of generating sounds having various levels are installed on the rear portion of the construction equipment according to the type of the construction equipment. Thus, since such construction equipment is used in various working fields, the level of ambient noise is variously formed in the working fields.
In addition, the back-up alarm device generating a sound having a predetermined level may be useless if it is employed in a working field having a high level of ambient noise. In order to solve the above problem, it is necessary to provide an intelligent back-up alarm device capable of automatically adjusting the loudness of the sound according to the environment in the working field.
According to conventional technologies, back-up alarm devices generating sounds having various loudness levels or a sound having the loudness level to be controlled according to the level of ambient noise during an alarm is generated with a high/low frequency compensation function for effectively removing high/low frequency signal components of detected ambient noise and a response compensation function for responding to an instant signal component of detected ambient noise are provided for mobile structures or industrial machines.
Until now, the back-up alarm device generating a sound having predetermined loudness is generally used for the construction equipment. Thus, when the construction equipment backs up in the working field having a high level of ambient noise, people cannot recognize the sound generated from the back-up alarm device because the predetermined sound loudness is too low for the above working field. In contrast, when the construction equipment backs up in the resident region, the sound generated from the back-up alarm device may cause noise pollution because the predetermined sound loudness of the sound generated from the back-up alarm device is too high for the resident region.
In order to solve the above problem, a back-up alarm device capable of controlling the loudness of a sound according to the loudness level of ambient noise has been suggested. However, since the back-up alarm device is attached to the rear portion of the construction equipment, the back-up alarm device may regard the sound generated from an engine of the construction equipment as ambient noise, so the back-up alarm device generates the sound with the maximum loudness. Thus, the back-up alarm device also causes sound pollution when it is used in the resident region.
The conventional technologies also provide a back-up alarm device, in which all kinds of switches of the construction equipment are connected to a buzzer sound output section through internal circuits, so that the driver can be alerted to whether the driver has precisely operated a desired functional switch based on a signal tone generated when the switches are operated. In addition, the driver can recognize whether the switches are operated based on the signal tone. Furthermore, a back-up alarm device having an error diagnosis function is provided in order to allow the driver to check whether the circuits and switches have defects during the switching operation.
As mentioned above, according to the conventional the back-up alarm installed in the construction equipment, the driver must directly control the loudness of the sound generated from the back-up alarm device based on ambient noise, so the driver of the construction equipment may feel inconvenienced in using the conventional back-up alarm device.